I don't think I expressed myself clearly. The fixture locations are marked and programmed. if the operator can't tell that he/she is at the right fixture, then there's no hope for them.

I'm looking for a way to let them know that the program they've loaded won't fit the fixture they've selected.
The usable table size is quite small, 7.5" X 13.5". These are set into the "soft limit" locations as there are no safeties on the mill at all. Each tag-holding depression has a specific fixture setting that denotes the lower left hand corner of the tag as a starting point for that particular tag. There are currently three fixtures programmed but there is room for and plans to create more.
ex: Fixture #2 is a 1" X 3" rectangular tag depression .07" deep. The offset is Xo .5 Yo 1.5 Zo -.355. What I'd like is the ability to have the program warn me if I try to load G-code that falls outside of X 0.5 to 3.5, Y 1.5 to 2.5, and Z -0.425 when the offsets for fixture #2 are in place. Fixture #3 is a complex shaped depression 1.75" at its widest point and 2.25" at its longest point, also .07" deep. The engraveable portion of the tag is approximately 1" x 1.5". the offset for fixture #3 is Xo .25, Yo 3.25, Zo -.355. When Fixture #3 is selected/loaded, I'd like a warning if the programmed Gcode falls outside of X 0.25 to 1.75, Y 3.25 to 4.25 and Z -0.425.
Currently, the softlimit warning is only generated if the code compiled exceeds X 0 to 7.5" or Y 0 to 13.5"